You are Gordon Freeman, a young research associate in the Anomalous
Materials Laboratory. You have limited security clearance and no
real idea of just how dangerous your job has become, until the morning
you are sent alone into the Test Chamber to analyze a strange
crystalline specimen. A routine analysis, they tell you. Until
something goes wrong. In this legendary FPS, players enlist the
help of traumatized scientists and trigger-happy security guards
to get through high-security zones, sneaking and fighting your way
through ruined missile silos and Cold War cafeterias, through
darkened airducts and subterranean railways. When you finally come
in sight of the surface, you realize that the inhuman monsters
aren't your only enemies-for the government has sent in ruthless
troops and stealthy assassins. Their orders seem to be that when
it comes to the Black Mesa, nothing gets out alive... and especially
not you.

Opposing Force returns the player to the Black Mesa facility,
but tells the tale from the perspective of Col. Adrian Shephard,
one of the soldiers sent to clean up the scientists and their
reality-altering mess. Just as in Half-Life, things quickly go
badly for Colonel Shephard and his men. Ambushed by aliens,
Adrian must fight his way through the ruins of the facility
in an attempt to reach a helicopter extraction point.

What makes Opposing Force shine is the way it expands on the story
of Half-Life. Colonel Shephard passes though areas that players of
Half-Life are sure to recognize, and he occasionally runs into
characters from the original game, including the infuriating Man
in Suit. Opposing Force also introduces several new weapons, such
as a sniper rifle (with scope), heavy machine gun, and a .357 Magnum
with a laser sight. There's even a "weapon" that is actually a
common alien creature from the first game; its unique features allow
it to be used as a kind of grappling hook.

Several new aliens make an appearance as well, almost
all of them deadly. They exhibit the same sophisticated
AI (artificial intelligence) as the monsters in Half-Life,
relentlessly and intelligently attacking Adrian as he makes
his way through the game's impressive levels. Fortunately,
Colonel Shephard's rank allows him to take command of any soldiers
he encounters. Riflemen and machine gunners can be ordered to
follow Adrian and provide covering fire, or assigned to guard a
door or room. Engineers can cut through locked or blocked doorways,
while Medics can heal the injured. Unlike Half-Life's solitary "me
against the world" game play, the addition of competent friendly
forces provides a feeling of camaraderie: there's nothing like
leading a squad of loyal Marines against an alien horde.

Barney Calhoun, that lovable security guard from Half-Life, finally
has his very own Half-Life adventure; Half-Life: Blue Shift! Developed
by Gearbox Software, who developed the award winning Half-Life addon
Half-Life: Opposing Force, Half-Life: Blue Shift introduces a whole
new Half-Life episode, as well as the full version of Half-Life:
Opposing Force. If you have yet to experience the joys of OpFor,
here is your chance!

In Half-Life: Blue Shift, you play Barney Calhoun who, as a security
guard, has access to far more areas that Gordon Freeman ever did!
Find out more about the Alien invasion and explore new areas of
the Black Mesa Research Facility which you never knew existed in
over 30 levels of action!